The Mechanical and Other Properties of Iron and Steel in Connection with Their Chemical Composition, 1891
https://books.google.com/books?id=-c8xAAAAMAAJ&pg=PA196&dq Whitworth Gun Steel was .30 - .42% carbon and .24 - .31% manganese.
Vickers was .24 - .27% carbon and .22% manganese
Krupp .46 - .52% carbon and .07 - .13% manganese
The modern industrial standard for AISI 1045 is .6 - .9% manganese. Bad things happen to steel when manganese combines with sulfides and metal oxides ie the Titanic
There were of course MANY variants of each new fangled steel. Scroll down about 2/3 at the link for lots of period composition reports
American Rifleman, April 8, 1915, Fred Adolph, More About Gun Barrel Steel
https://books.google.com/books?id=EpcwAQAAMAAJ&pg=PA25&lpg Krupp makes 200 kinds of steels
